Question

我有地图视图，我喜欢使用叠加方法绘制线条，当我按下按钮时，我添加了两个位置纬度和经度来绘制它们之间的线，但是当我第二次按下我提供的新坐标和新线时在地图上有吸引力，但之前的叠加路径消失了，但我也需要在同一张地图上预先路径

这是我的代码。

- (IBAction)refreshMapMethod:(id)sender

{


 int kk=[[NSUserDefaults standardUserDefaults]integerForKey:@"ham"];




    if (kk==1)
    {
         CLLocationCoordinate2D coordinateArray[2];
        coordinateArray[0] = CLLocationCoordinate2DMake(12.915181,+77.626055);
        coordinateArray[1] = CLLocationCoordinate2DMake(12.892156, +77.582188);
        self.routeLine = [MKPolyline polylineWithCoordinates:coordinateArray count:2];
        [self.myMapView setVisibleMapRect:[self.routeLine boundingMapRect]];

        [self.myMapView addOverlay:self.routeLine];
        [[NSUserDefaults standardUserDefaults]setInteger:2 forKey:@"ham" ];


    }


    if (kk==2)
    {
        CLLocationCoordinate2D coordinateArray[2];
        coordinateArray[0] = CLLocationCoordinate2DMake(12.892156,+77.426055);
        coordinateArray[1] = CLLocationCoordinate2DMake(12.892156, +77.582188);
        self.routeLine = [MKPolyline polylineWithCoordinates:coordinateArray count:2];
        [self.myMapView setVisibleMapRect:[self.routeLine boundingMapRect]];

        [self.myMapView addOverlay:self.routeLine];
        [[NSUserDefaults standardUserDefaults]setInteger:3 forKey:@"ham" ];


    }
    if (kk==3)
    {
        CLLocationCoordinate2D coordinateArray[2];
        coordinateArray[0] = CLLocationCoordinate2DMake(12.892156, +77.382188);
        coordinateArray[1] = CLLocationCoordinate2DMake(12.892156, +77.282188);
        self.routeLine = [MKPolyline polylineWithCoordinates:coordinateArray count:2];
        [self.myMapView setVisibleMapRect:[self.routeLine boundingMapRect]];

        [self.myMapView addOverlay:self.routeLine];
        [[NSUserDefaults standardUserDefaults]setInteger:3 forKey:@"ham" ];


    }



    CLLocationCoordinate2D zoomLocation;
    zoomLocation.latitude= 12.915181;
    zoomLocation.longitude=77.626055;

    MKCoordinateRegion viewRegion=MKCoordinateRegionMakeWithDistance(zoomLocation, 3*METERS_PER_MILE, 3*METERS_PER_MILE);

    [self.myMapView setRegion:viewRegion animated:YES];


 [[NSUserDefaults standardUserDefaults]setInteger:2 forKey:@"change" ];


}

调用叠加方法..

-(MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id<MKOverlay>)overlay


{

    if(overlay == self.routeLine)
    {
        if(nil == self.routeLineView)
        {
          self.routeLineView = [[MKPolylineView alloc] initWithPolyline:self.routeLine];



            self.routeLineView.fillColor = [UIColor redColor];
            self.routeLineView.strokeColor = [UIColor redColor];
            self.routeLineView.lineWidth = 5;

        }

        return self.routeLineView;
    }

    return nil;
}

请以同样的方式或其他任何替代方式向我提供解决方案。

比你。

Answer 1

这是因为您只允许viewForOverlay函数返回self.routeline的视图，而您只有其中一个。{1}}。对viewForOverlay的每次其他调用都将返回nil，因此不会被绘制。您需要做的是绘制所有叠加层。

-(MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id<MKOverlay>)overlay
{
    MKPolylineView* routeLineView = [[MKPolylineView alloc] initWithPolyline:(MKPolyLine)overlay];
    routeLineView.fillColor = [UIColor redColor];
    routeLineView.strokeColor = [UIColor redColor];
    routeLineView.lineWidth = 5;

    return routeLineView;
}

你可能需要做更多的事情，例如首先检查叠加层实际上是折线，但这应该足以让你前进。

在iOS6中将覆盖线保留在地图视图上

1 个答案: